prickly branching sponge
This rubbery prickly sponge usually yellow or with yellow tips is
commonly seen on coral rubble on many of our Southern shores.
variable in shape from knobs, lobes, to slender branching stems (8-12cm)
emerging from an encrusting base (20-30cm). The sponge can cover large
areas of coral rubble or small stones. Tips rounded or flattened.
The surface feels rubbery and slippery with small bumps that appear
spiky and prickly when the sponge is out of water. There are many
tiny holes sprinkled all over the sponge. Colours range from bright
yellow, green-yellow to olive. Often mainly dark or olive green with
yellowish tips. The sponge's species name 'purpurea' means purple.
Which seems rather odd as they are not purple at all when alive. A
dead sponge, however, rapidly oxidises to a dark brown or deep purple.
As taxonomic work on sponges is often based on preserved specimens,
this is probably how this sponge got its scientific name.
Sometimes confused with Mustard sponge (Dactylospongia elegans,
Family Thorectidae) can look very similar. The two kinds of sponges
are difficult to tell apart in the field.
Sponging clams: Sometimes, the
sponge is inhabited by Sponge
finger oysters (Vulsella sp.), a kind of clam that lives
only in sponges. These are completely covered by the sponge, with
only a slit on the surface of the sponge where the bivalve's shell
opening is. Often, these bivalves result in flat blade or leaf-like
protrusions in the sponge.
Human uses: This sponge contains
the chemical psammaplin A which is reported to be a powerful blocker
of several components of the processing machinery in cancer cells,
preventing them from growing and dividing. More
Beting Bemban Besar, May 11
Usually dark with yellow tips.
Many tiny holes on a bumpy surface.
Sisters Island, Jan 12
St. John's Island, Sep 04
Sisters Islands, Dec 05
Pulau Pawai, Dec 09
Pulau Biola, Dec 09
Terumbu Berkas, Jan 10
*Species are difficult
to positively identify without close examination.
On this website, they are grouped by external features for convenience
prickly branching sponges on Singapore shores